How to overlay a picture with transparency overr a movie clip?
Here is the asked answer:

in comments above I suggested a method in less than 15 words, but there is also another way that could be even faster or simpler, so this answer will be double:

anyway, you start from this situation, where you have an image with transparency and an underlying video, and you wish to overimpose the image to the video using that transparency.




method 1: set the image blend type to alpha over


with the image strip selected (RMB) in the "properties" panel (press N to show/hide) there's a "blend" type selector, by default set to "replace". Set it to "alpha over", done.





in this case you can use the slider below "blend" to set (or animate) the opacity.




method 2: add an "alpha over" effect strip


with both the video and the image strips selected  (shiftRMB) , add an effect strip "alpha over". Done.





in this case, to set the opacity, you can select the effect strip, and in the "properties" panel (press N to show/hide) unset the "default fade" checkbox, and then set (or animate) the "fade" you wish from that.